1. Technical Field
The present invention relates to a wooden member assembly made of a wooden material, such a laminated wood formed by bonding small cross-section wood pieces or a natural wood piece, and a tensile member installed in an axial direction thereof, wherein prestress has been introduced into the wooden member by the tensioning force of the tensile member.
2. Related Art
A wooden building may be required to have a structure provided with a large space, such as a room in which many people can join or a parking space where a plurality of cars can be parked. To provide such a large space, cross members, such as beams, must be spanned between columns provided at large intervals to support the load from the roof or the upper floors.
A wooden material reinforced using a steel member or the like is sometimes used as a cross member which is spanned across a large distance to support the load from the upper floors or roof. For example, Patent Literature 1 discloses a reinforced wooden structural member composed of a wooden substrate reinforced by a reinforcing material. The reinforced wooden structural member is composed of a substrate formed of a natural wood piece or laminated wood and having a through hole extending in the longitudinal direction thereof, and a reinforcing steel rod is installed through the through hole. Threads are formed at both ends of the reinforcing steel rod, and the reinforcing steel rod is fixedly secured to the reinforced wooden structural member by nuts threadably mounted thereon.    [Patent Literature 1] JP-Utility Model Publication No. 3152531
In such a reinforced wooden structural member, both ends of the reinforcing steel rod axially (longitudinally) extending through the substrate are fixedly secured by nuts via springed washers in cutout recesses formed in the end faces of the substrate. Thus, a tensioning force has been introduced into the reinforcing steel rod, and the reactive force of the tensioning force acts on the reinforced wooden structural member via the springed washers. Because wood has a lower elastic modulus than metals and so on, the contact face may be deformed when a large force is applied thereto from a metal member such as a washer. When the contact area of the metal member is increased to prevent such deformation, the structure by which the tensile member such as the reinforcing steel rod is fixed becomes large. Then, the structure by which the tensile member is fixed may be exposed from the side surfaces of the wooden material or may prevent an end of the wooden material from being joined to another member.
The present invention has been made in view of above circumstances, and it is, therefore, an object of the present invention to provide a wooden member assembly formed of a wooden material and configured to be easily joined to another member and to have a good appearance by decreasing the size of the fixation structure for a tensile member installed to improve the load bearing performance of the wooden member.